The following relates to wireless communication systems, and more particularly to beam management for various levels of beam correspondence.
Wireless communication systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code-division multiple access (CDMA) systems, time-division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, and orthogonal frequency-division multiple access (OFDMA) systems.
By way of example, a wireless multiple-access communication system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, otherwise known as user equipments (UEs). A base station may communicate with UEs on downlink channels (e.g., for transmissions from a base station to a UE) and uplink channels (e.g., for transmissions from a UE to a base station).
Wireless communication systems may operate in millimeter wave (mmW) frequency ranges, e.g., 28 GHz, 40 GHz, 60 GHz, etc. Wireless communication at these frequencies may be associated with increased signal attenuation (e.g., path loss), which may be influenced by various factors, such as temperature, barometric pressure, diffraction, etc. As a result, signal processing techniques, such as beamforming, may be used to coherently combine energy and overcome the path losses at these frequencies. Due to the increased amount of path loss in mmW communication systems, transmissions from the base station and/or the UE may be beamformed.
Wireless communication between two wireless nodes, e.g., between a base station and a UE, may use beams or beamformed signals for transmission and/or reception. A base station may transmit beamformed signals on downlink (DL) beams associated with the base station. A UE may receive a signal on one or more DL beams associated with the UE. The DL beam associated with the base station and the DL beam associated with the UE used for DL communication between the base station and the UE constitute a DL beam pair. Similarly, a UE may transmit beamformed signals on uplink (UL) beams associated with the UE. A base station may receive a signal on one or more UL beams associated with the base station. The UL beam associated with the UE and the UL beam associated with the base station used for UL communication between the UE and the base station constitute an UL beam pair. In some instances, the DL beam pair and the UL beam pair may be the same (e.g., may represent the same beam pairs). In other instances, differences may exist between a DL beam pair and an UL beam pair.